Enhanced thermal conductivity by combined fillers in polymer composites

This paper reports a new way of improving the thermal conduction property of polymer composites composed of silicone rubber and combined fillers obtained by attaching spherical alumina particles to carbon fibers using spray-drying method. The experimental results showed that the thermal conductivities of the polymer composites were 16, 28, 30, 32, and 42% higher than those of composites with untreated carbon fibers at the same content. The analysis based on effective medium theory revealed that the interface thermal resistance decreases from 1.2 × 10−6 m2 K/W to 8.5 × 10−7 m2 K/W in polymer composites. It demonstrates that the combined fillers could decrease the interface thermal resistance to improve the thermal conduction property of polymer composites, and thus are promising for the development of high-performance thermally conductive products.